Networks, such as using Dense Wave Division Multiplexing (DWDM), Optical Transport Network (OTN), Ethernet, Multiprotocol Label Switching (MPLS), and the like, are deploying control plane systems and methods. Control planes provide an automatic allocation of network resources in an end-to-end manner. Example control planes may include Automatically Switched Optical Network (ASON) as defined in ITU-T G.8080/Y.1304, Architecture for the automatically switched optical network (ASON) (February 2012), the contents of which are herein incorporated by reference; Generalized Multi-Protocol Label Switching (GMPLS) Architecture as defined in IETF Request for Comments (RFC): 3945 (October 2004) and the like, the contents of which are herein incorporated by reference; Optical Signaling and Routing Protocol (OSRP) from Ciena Corporation which is a signaling and routing protocol similar to Private Network-to-Network Interface (PNNI) and Multi-Protocol Label Switching (MPLS); or any other type control plane for controlling network elements at multiple layers, and establishing connections among nodes. Control planes are configured to establish end-to-end signaled connections such as Subnetwork Connections (SNCs) in ASON or OSRP, and Label Switched Paths (LSPs) in GMPLS and MPLS. Note, as described herein, SNCs and LSPs can generally be referred to as services or calls in the control plane. Control planes use available paths to route the services and program the underlying hardware accordingly.
At the optical layer (also referred to as the photonic layer, DWDM layer, Layer 0, etc.) the distributed control plane architecture for Layer 0, restoration (where every Optical Add/Drop Multiplexer (OADM) node effectively works as a control plane node) fails to trigger restoration for individual optical channels, when communication is lost with an intermediate control plane node on the channel path. The existing control plane framework can only handle restoration in such scenario if an optical line failure is detected at both neighboring degrees of the troubled node. As is known in the art, an OADM node can have one or more degrees and each degree represents an optical path of ingress in and egress from the OADM node. In any other case, such as an electrical power down on a control plane enabled shelf or a shelf processor failure in an intermediate node (such failures only affecting a subset of degrees of the OADM node), downstream control plane nodes do not receive any fault notification from upstream control plane nodes, and similarly, upstream originating nodes lose their visibility on faults taking place downstream of the faulted node. As a result, on a traffic fault, originating Layer 0 control plane nodes fail to take appropriate actions to restore optical channels on a different path.
That is, when not all channels are faulted, the control plane cannot trigger restoration for an individual or a partial set of channels when there is no line fault detected or no line fault notification is received from other control plane nodes. An all-channel fault would have indicated a potential line fault. With a partial set of channel fault, a control plane originating node does not know where the fault is coming from. For example, this can be because a control plane node processor is down in an intermediate node, all the fault propagation (in-band communications) cannot bypass the faulty node.